MIT Working on ElectroChemical Energy Harvesting #WearableWednesday
Usually when I think of energy harvesting, I think of flex sensors or capturing movement. Well, a team at MIT has figured out a way to capture even small movements according to a post by PCWorld. According to the team’s paper, “The device achieves long current pulse duration, which has not been achieved by other types of mechanical energy-harvesting devices.” In fact, their device achieved a generating capacity of 15%. Here’s the secret sauce:
Specifically, their technology uses two thin sheets of lithium alloys as electrodes, with a layer of porous polymer soaked with liquid electrolyte in between. When bent even just slightly, the layered composite produces a counteracting voltage and an electrical current in the external circuit between the two electrodes, which can be then used to power other devices.
They use the term “lithium migration” to describe the resulting current in the device when there is asymmetric stress creating the chemical difference. This is quite different from the two popular energy harvesting methods, triboelectric (think rubbing a balloon against wool), or piezoelectric (using crystals). MIT’s method is more cost effective.
Such traditional approaches have “high electrical impedance and bending rigidity, and can be quite expensive,” said Ju Li, Battelle Energy Alliance Professor in Nuclear Science and Engineering and professor of materials science and engineering at MIT.
Most harvesting methods are also meant for high frequency ranges, but this particular method works well for low frequency ranges like walking. So, this device is ideal for small movements in the arm and leg. Of course when you think of repetitive motion, you may worry about stress, but MIT’s device has held up well, keeping it’s integrity and performance even after 1,500 cycles. So, there is plenty of excitement about potential uses including “biomedical devices or embedded stress sensors in roads, bridges or even keyboards”. Although you may not have a lab at home fit for working on electrochemical devices, you can discover the power of movement and trigger your own reactions with an Arduino and one of our flex sensors. Try it in a glove or an elbow area of your sweatshirt and decide what event you would like to have happen. Could be nice for cosplay when you want to initiate a light sequence on a costume!
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.